1D4 & 60D
I received an email that suggested select 1D4 and 60D's are being tested with 3″ OLED screens. Most of the test cameras are equipped with LCD screens.
1D4 to be USB 3.0 ready. The initial camera shipments may come with it locked out, and be later turned on with a firmware upgrade as the spec reaches the masses sometime in 2010.
note: I don't have the technical knowledge to know if you can turn on usb 3.0 at a later date. If anyone has some insight, i'd appreciate it.
GPS & Wifi
The source says GPS will be built into the 1D4 and not the 60D. Wifi will be an addon product for both cameras.
The same email states August 25, 2009 for the official announcement.